The present invention is related to input power management, and more specifically to test circuitry for automatically detecting singular faults in diode or'd power bus circuits.
A number of applications, such as safety critical avionics, make use of independent, redundant power input sources. In the event that one or more of the input sources fails, another of the available redundant power input sources is employed to ensure an uninterrupted supply of power.
FIG. 1 is a circuit diagram illustrating a common diode or'd power bus circuit configuration used to combine independent, redundant power input sources into a common internal source. The diode or'd power bus circuit consists of a number of power diodes (labeled PD1-PDN), each connected to one of the redundant power input sources. The redundant power source providing the highest quality power causes the associated diode to conduct, resulting in the highest level of quality power being propagated through the diode or'd power bus circuit and provided as the internal power source. The remainder of the power diodes within the diode power input circuit provide isolation to prevent the remaining input sources from sourcing power to the internal power source (i.e., the other diodes would be in a non-conducting state).
In the event that the redundant power supply being used to generate the internal power source failed, one of the other redundant power sources would cause an associated diode to conduct, and the power input source connected to the conducting diode would be propagated through the diode or'd power bus circuit and provided as the internal power source. However, a faulty diode (i.e., a diode that fails to conduct) will result in the interruption of the internal power source.
Therefore, it would be desirable to provide a system/method of detecting singular faults within a diode or'd power bus circuit.